scholarly journals The Relationship between Soil Moisture and Soil Water Repellency Persistence in Hydrophobic Soils

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2322 ◽  
Author(s):  
Mohamed Bayad ◽  
Henry Wai Chau ◽  
Stephen Trolove ◽  
Jim Moir ◽  
Leo Condron ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Drop ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Sigmoidal Curve ◽  
New Equation ◽  
Two Parameters ◽  
The Relationship ◽  
Penetration Time

In this work, we modelled the response of soil water repellency (SWR) persistence to the decrease in moisture in drying soils, and we explored the implication of soil particle size distribution and specific surface area on the SWR severity and persistence. A new equation for the relationship between SWR persistence and soil moisture (θ) is described in this paper. The persistence of SWR was measured on ten different hydrophobic soils using water drop penetration time (WDPT) at decreasing levels of gravimetric water content. The actual repellency persistence showed a sigmoidal response to soil moisture decrease, where Ra(θ)=Rp/1+eδ(θ−θc). The suggested equation enables one to model the actual SWR persistence (Ra) using θ, the potential repellency (Rp) and two characteristic parameters related to the shape of the response curve. The two parameters are the critical soil moisture θc, where the Ra increase rate reaches its maximum, and the parameter δ affecting the steepness of the curve at the inflexion point of the sigmoidal curve. Data shows that both soil carbon and texture are controlling the potential SWR in New Zealand pastures.

The impact of heating on the hydraulic properties of soils sampled under different plant cover

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Viliam Novák ◽  
Ľubomír Lichner ◽  
Bin Zhang ◽  
Karol Kňava
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Water ◽  
Water Retention ◽  
Water Drop ◽  
Sampling Site ◽  
Water Repellency ◽  
Saturated Hydraulic Conductivity ◽  
Soil Water Repellency ◽  
The Impact ◽  
Penetration Time

AbstractThe impact of heating on the peristence of water repellency, saturated hydraulic conductivity, and water retention characteristics was examined on soils from both forest and meadow sites in southwest Slovakia shortly after a wet spell. The top 5 cm of meadow soils had an initial water drop penetration time WDPT at 20°C of 457 s, whereas WDPT in the pine forest was 315 s for the top 5 cm and 982 s if only the top 1 cm was measured. Heating soils at selected temperatures of 50, 100, 150, 200, 250 and 300°C caused a marked drop in water drop penetration time WDPT from the initial value at 20°C. However, samples collected in different years and following an imposed cycle of wetting and drying showed much different trends, with WDPT sometimes initially increasing with temperature, followed by a drop after 200–300°C. The impact of heating temperature on the saturated hydraulic conductivity of soil was small. It was found for both the drying and wetting branches of soil water retention curves that an increase in soil water repellency resulted in a drop in soil water content at the same matric potential. The persistence of soil water repellency was strongly influenced by both the sampling site and time of sampling, as it was characterized by the results of WDPT tests.

Soil water repellency persistence after recurrent forest fires on Mount Carmel, Israel

2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Forest Fires ◽  
Water Drop ◽  
Chemical Properties ◽  
Water Repellency ◽  
Mediterranean Ecosystem ◽  
Long Term Effects ◽  
Soil Water Repellency ◽  
Chemical Properties Of Soils

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

scholarly journals Variability of water repellency in sandy forest soils under broadleaves and conifers in north-western Jutland/Denmark

2008 ◽  
Vol 3 (Special Issue No. 1) ◽  
pp. S155-S164 ◽  
Author(s):  
N.A Wahl
Keyword(s):  
Soil Water ◽  
Preferential Flow ◽  
Water Drop ◽  
Water Repellency ◽  
Climatic Conditions ◽  
Tree Age ◽  
Critical Surface ◽  
Soil Water Repellency ◽  
Wide Range ◽  
North Western

Soil water repellency has important consequences for ecological and hydrological properties of soils and usually retards infiltration capacity and induces preferential flow. This phenomenon has been known to occur on a wide range of sites under a variety of climatic conditions. The objective of this study was to investigate and characterize soil water repellency on forest sites with identical substrate and climatic conditions, differing in tree age and species. In the Vester Torup Klitplantage, an area comprising a conifer dominated forest plantation stocking on sandy deposits in a coastal setting near the Jammer Bay in north-western Jutland/Denmark, four different forest plots were investigated for water repellency effects four times in 2005. To measure soil water repellency, the water drop penetration time test and the critical surface tension test were carried out. Both tests revealed a seasonal variability in water repellency, exhibiting the highest water repellency for the upper 10 cm of the soil during the summer months, whereas the variability between the different plots seems to be less significant. There was no coherence between humus forms, thickness of litter layer and water repellency.

The effect of soil moisture extremes on the pathways and forms of phosphorus lost in runoff from two contrasting soil types

Soil Research ◽  
2017 ◽  
Vol 55 (1) ◽  
pp. 19 ◽  
Author(s):  
B. Simmonds ◽  
R. W. McDowell ◽  
L. M. Condron
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Surface Runoff ◽  
Water Drop ◽  
Organic Soil ◽  
Surface Flow ◽  
Olsen P ◽  
Excess Surface ◽  
Infiltration Excess ◽  
Penetration Time

Soil moisture and Olsen P concentrations play an important role in phosphorus (P) losses in runoff. Under moisture-rich anaerobic conditions, the reduction of Fe-oxides dissolves P from the soil into solution that may be available for loss by transport processes. Under very dry conditions, soil hydrophobicity induced by soil organic C can exacerbate infiltration-excess surface flow and soil erosion. Our hypotheses were as follows: (1) rainfall applied to a dry soil would cause greater particulate P losses in surface runoff due to hydrophobicity; (2) P losses from a wet soil would be dominated by drainage and filtered P; and (3) both runoff processes would result in environmentally unacceptable P losses at agronomically productive Olsen P concentrations depending on the sorption capacity (anion storage capacity; ASC) of the soil. Superphosphate was added to a Brown and Organic soil (Olsen P initially 7 and 13mgL–1 respectively) to create a range of Olsen P concentrations. Soils were placed in boxes, soil moisture adjusted (<10% or 90% available water holding capacity) and artificial rainfall applied at a rate equivalent to a storm event (5-year return interval; 30–35mmh–1) and surface runoff and drainage collected. Surface runoff was measured as infiltration-excess surface flow from dry Organic soil (water drop penetration time >3600s), and as saturation-excess surface flow from the wet Brown soil (water drop penetration time <5s). Total P (TP) concentrations in surface flow from both soils increased linearly with Olsen P concentration. Compared with dry Organic soil, the wet Brown soil lost a greater proportion of TP as particulate via surface runoff. However, due to the high hydraulic conductivity and low ASC, the most important pathway for the Organic soil, wet or dry, was filtered P loss in drainage. These data can be used to more effectively target strategies to mitigate P losses.

scholarly journals Evaluation of Direct Application of Enzymes to Remediate Soil Water Repellency

HortScience ◽  
2014 ◽  
Vol 49 (5) ◽  
pp. 662-666
Author(s):  
Lusheng Zeng ◽  
Jiayang Liu ◽  
Robert N. Carrow ◽  
Paul L. Raymer ◽  
Qingguo Huang
Keyword(s):  
Water Management ◽  
Soil Water ◽  
Crop Production ◽  
Water Drop ◽  
Water Repellency ◽  
Direct Application ◽  
Water Control ◽  
Soil Water Repellency ◽  
Incubation Study ◽  
Logarithmic Relationship

Organic coatings on sand particles can cause soil water repellency (SWR) where a soil does not spontaneously wet; this leads to challenges in water management and crop production. In laboratory studies, we evaluated a novel approach using direct application of 10 enzymes at three (low, medium, high) dosages to remediate SWR on two sand turfgrass soils in a 3-day incubation study and a second study at high dosage with 1-day incubation. A soil:solution ratio of 1:1 (10 g soil and 10 mL solution) was used and a deionized water control included. For Soil 7, a very strongly hydrophobic soil from a localized dry spot turfgrass area with a water drop penetration time (WDPT) of 7440 seconds (untreated) and 332 to 338 seconds (water-treated), the high dosage rates of laccase, chitinase, and protease at 1 and 3 days incubation resulted in WDPT of less than 60 seconds (i.e., hydrophilic soil). Pectinase exhibited similar results only in the 3-day incubation study. On the strongly hydrophobic Soil 21 (WDPT of 655 seconds untreated; 94 to 133 water-treated) from the dry area of a fairy ring-affected area on a turfgrass site, high dosages of chitinase, laccase, pectinase, and protease reduced WDPT to less than 60 seconds in both studies; and medium dosage rates were also effective for all but protease in the 3-day incubation study. Each of the four most effective enzymes for reducing WDPT, noted previously, demonstrated a significant exponential or logarithmic relationship between decreasing WDPT and increasing enzyme dosage. Further studies in field situations will be required to determine enzyme effectiveness on SWR and water management.

Soil Water Repellency: A Method of Soil Moisture Sequestration in Pinyon-Juniper Woodland

2010 ◽  
Vol 74 (2) ◽  
pp. 624-634 ◽  
Author(s):  
David A. Robinson ◽  
Inma Lebron ◽  
Ronald J. Ryel ◽  
Scott B. Jones
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Juniper Woodland

Temporal fluctuations in soil water repellency following wildfire in chaparral steeplands, southern California

2005 ◽  
Vol 14 (4) ◽  
pp. 439 ◽  
Author(s):  
K. R. Hubbert ◽  
V. Oriol
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Water Repellency ◽  
Weather Conditions ◽  
Antecedent Rainfall ◽  
Soil Water Repellency ◽  
Soil Wetness ◽  
Moisture Conditions ◽  
East West ◽  
Seasonal Weather

Soil water repellency is particularly common in unburned chaparral, and its degree and duration can be influenced by seasonal weather conditions. Water repellency tends to increase in dry soils, while it decreases or vanishes following precipitation or extended periods of soil moisture. The 15 426 ha Williams Fire provided an opportunity to investigate post-fire fluctuations in water repellency over a 1-year period. Soil water repellency was measured at the surface, and at 2-cm and 4-cm depths along six east–west-positioned transects located within the chaparral-dominated San Dimas Experimental Forest. During the winter and spring, seasonal variation in the degree of surface water repellency appeared to be inversely proportional to antecedent rainfall and soil moisture conditions. Precipitation through December reduced the proportion of surface ‘moderate or higher repellency’ from 49 to 4% as soil wetness increased to 12%. Throughout the summer, soil wetness remained below 2%; however, surface soils remained ‘wettable’, with the proportion of surface ‘moderate or higher repellency’ never returning to the early post-fire amount of 47%. Interestingly, at the 4-cm depth, the proportion of ‘moderate or higher repellency’ remained at levels >25% throughout the summer dry season.

Sign in / Sign up

Export Citation Format

Share Document